STUDY OBJECTIVE--The aim of the study was to investigate the incidence of cancer in Asians living in Bradford. DESIGN--Cancer registrations were obtained from the Yorkshire Regional Cancer Registry for the six year period 1979-1984. Registrations relating to persons of Asian background were extracted using forenames and surnames. Data were analysed by disease category and age and sex specific incidence rates were calculated. These were compared with expected incidence rates for the non-Asian population and with rates for the Indian subcontinent derived from the Bombay Cancer Registry. SETTING--Data collection was confined to the Bradford Metropolitan District, population 449,897 (1981). SUBJECTS--The Asians studied originated from Pakistan (65%), India (28%), Bangladesh (4%), and East Africa (3%). The total Asian population of the Bradford Metropolitan District was approximately 45,000. MAIN RESULTS--Over the study period there were 178 Asian cancer registrations. The overall standardised registration ratio was 53.7 for males (100 cases, 95% confidence interval 43-64), and 43.5 for females (78 cases, 95% CI 34-53). The standardised registration ratios for cancer of the hypopharynx in males and gall bladder in females were significantly raised. There was a particularly low incidence of cancer of the stomach, large bowel, lung, skin, and bladder in males, and of skin, breast, cervix (in situ), and ovary in females. The analyses suggested that lung and breast cancer incidence may be increasing towards the non-Asian level. In situ cancer of cervix in Asians shows no evidence of the high rates found in younger non-Asian age groups. CONCLUSIONS--Lower incidence of many cancers in Asians may be due to lower exposure to major risk factors. Demographic change resulting in increased exposure to these risk factors can be expected to result in an increase in cancer incidence in Asians.